Identifying Host Names and IP Addresses
Identifying Host Names and IP Addresses
This article presents a mixed bag of Oracle functionality relating to the identification of host names and IP addresses for Oracle clients and servers.
UTL_INADDR
The UTL_INADDR package was introduced in Oracle 8.1.6 to provide a means of retrieving host names and IP addresses of remote hosts from PL/SQL.
The GET_HOST_ADDRESS function returns the IP address of the specified host name.
SQL> SELECT UTL_INADDR.get_host_address('bart') FROM dual;
UTL_INADDR.GET_HOST_ADDRESS('BART')
--------------------------------------------------------------------------------
192.168.2.4
SQL>
The IP address of the database server is returned if the specified host name is NULL or is omitted.
SQL> SELECT UTL_INADDR.get_host_address from dual; GET_HOST_ADDRESS -------------------------------------------------------------------------------- 192.168.2.5 SQL>
An error is returned if the specified host name is not recognized.
SQL> SELECT UTL_INADDR.get_host_address('banana') from dual;
SELECT UTL_INADDR.get_host_address('banana') from dual
*
ERROR at line 1:
ORA-29257: host banana unknown
ORA-06512: at "SYS.UTL_INADDR", line 19
ORA-06512: at "SYS.UTL_INADDR", line 40
ORA-06512: at line 1
SQL>
The GET_HOST_NAME function returns the host name of the specified IP address.
SQL> SELECT UTL_INADDR.get_host_name('192.168.2.4') FROM dual;
UTL_INADDR.GET_HOST_NAME('192.168.2.4')
--------------------------------------------------------------------------------
bart
SQL>
The host name of the database server is returned if the specified IP address is NULL or omitted.
SQL> SELECT UTL_INADDR.get_host_name FROM dual; GET_HOST_NAME -------------------------------------------------------------------------------- C4210gR2 1 row selected. SQL>
An error is returned if the specified IP address is not recognized.
SQL> SELECT UTL_INADDR.get_host_name('1.1.1.1') FROM dual;
SELECT UTL_INADDR.get_host_name('1.1.1.1') FROM dual
*
ERROR at line 1:
ORA-29257: host 1.1.1.1 unknown
ORA-06512: at "SYS.UTL_INADDR", line 4
ORA-06512: at "SYS.UTL_INADDR", line 35
ORA-06512: at line 1
SQL>
SYS_CONTEXT
The SYS_CONTEXT function is able to return the following host and IP address information for the current session:
TERMINAL- An operating system identifier for the current session. This is often the client machine name.HOST- The host name of the client machine.IP_ADDRESS- The IP address of the client machine.SERVER_HOST- The host name of the server running the database instance.
The following examples show the typical output for each variant.
SQL> SELECT SYS_CONTEXT('USERENV','TERMINAL') FROM dual;
SYS_CONTEXT('USERENV','TERMINAL')
--------------------------------------------------------------------
marge
1 row selected.
SQL> SELECT SYS_CONTEXT('USERENV','HOST') FROM dual;
SYS_CONTEXT('USERENV','HOST')
--------------------------------------------------------------------
marge
1 row selected.
SQL> SELECT SYS_CONTEXT('USERENV','IP_ADDRESS') FROM dual;
SYS_CONTEXT('USERENV','IP_ADDRESS')
--------------------------------------------------------------------
192.168.2.3
1 row selected.
SQL> SELECT SYS_CONTEXT('USERENV','SERVER_HOST') FROM dual;
SYS_CONTEXT('USERENV','SERVER_HOST')
--------------------------------------------------------------------
C4210gr2
1 row selected.
SQL>
V$INSTANCE
The HOST_NAME column of the V$INSTANCE view contains the host name of the server running the instance.
SQL> SELECT host_name FROM v$instance; HOST_NAME ------------------------------------------------ C4210gR2 1 row selected. SQL>
V$SESSION
The V$SESSION view contains the following host information for all database sessions:
TERMINAL- The operating system terminal name for the client. This is often set to the client machine name.MACHINE- The operating system name for the client machine. This may include the domain name if present.
The following examples show the typical output for each column.
SQL> SELECT terminal, machine FROM v$session WHERE username = 'TIM_HALL'; TERMINAL MACHINE ------------------------------ ---------------------------------------------------- MARGE ORACLE-BASE\MARGE 1 row selected. SQL>
For more information see:
